Stylus head for recording and reproducing sound records



M y 1943- E. R. HARRIS 2,318,308

STYLUS HEAD FOR RECORDING AND REPRODUCING SOUND RECORDS Filed Jan. 15, 1941 lNvEN roR. Fag/4rd R060 Harris ATTORNEY.

Patented May- 4, 1943 STYLUS HEAD FOR RECORDING AND REPRODUCING SOUND RECORDS Edward Robert Harris, Los Angeles, Calif., as-

signor to Isabelle Russell Harris, Los

Calif.

Angeles,

Application January 15, 1941, Serial No. 374,536 3 Claims. (CL 179-10041) My invention relates to mechanisms used in stylus heads for recording and reproducing sound records.

This mechanism is adapted to be applied and be used with any phonographic mechanism wherein what is known as scratch or sound groove mechanisms are involved, either lateral or hill and dale records are employed.

An object of my invention is to produce a head having special mechanisms which adapt the head to be used with high eiliciency in any apparatus in use of those types of records.

Another object of my invention is to provide special mechanisms whereby two types of stylus points or needles may be used alternately. one

for cutting a record and the other for reproducing the sound from a record, and each of these stylus points mounted to be actuated in relation to the one electromagnetic coil involved with what is known as amplifying electrical mechanisms.

Another object of my invention is to provide special details of construction and arrangement of the parts for simplicity and low cost of pro,- duction.

Another object of my invention is to provide mechanisms which increase the efliciency of the performance of recording and reproducing of sound wherein a sound groove in a record is used.

Reference will be had to the accompanying drawing in which Fig. 1 is a longitudinal side elevation of the stylus head. Fig. 2 is a detail elevation on line 2-2 of Fig. 1. Fig. 3 is a plan on line 3-3 of Fig. 1 showing the mechanisms on the inside of the housing of the stylus head. Fig. 4 is a vertical section on line 4-4 of Fig. 3. Fig. 5 is a vertical section of a detail on line 55 of Fig. 4. Fig. 6 is a transverse vertical section on line 66 of Fig. 4. Fig. 7 is a perspective view of a depth gage for limiting the depth of a stylus point into a sound groove.

In the drawing P indicates a post or a suitable part of a phonograph machine to which a stylus head arm is supported in service position in the machine. W indicates the electrical conductor wires connecting the stylus head mechanisms to any suitable electrical amplifying means. These wires enter through the post P and are trained up through and out of one side of a block B and into and'along the under side of a stylus arm A to the stylus carrying means. The block B is provided with a tubular extension T mounted into the supporting post P and adapted to revolve around in said post P and be retained in a post P whereby the tube T with its block 3 may be clamped in fixed position as desired.

The arm A is supported in hinged relation with the block B by trunnion pins 4, see Fig. 2, whereby the arm A may be rocked up and down on the pins 4. The arm A is supported upwardly in substantially a horizontal position by a spring 5 which is fixed into the block B by a screw 6, see Fig. 1. An'adjustable contact of the arm A with the spring 5 is obtained by the set screws 1 and 8 whereby the gravity load of the outer portion of the arm A rests on the spring 5. The spring is adjusted to act as a counter balancing feature of the weight of the stylus head mechanisms.

The-arm A is provided with a housing head H enclosingthe stylus supporting mechanisms. This head H is provided with a bottom or frame block member F which carries the stylus mechanisms. This block F is fastened to the housing H by screws 9.

The stylus mechanisms are mounted on the frame block member F and can be all assembled thereon and then this block placed into the fixed position as desired by a set screw 3 in the housing H.

The mechanisms are provided with a primary recording stylus S and a secondary reproducing stylus R both of which are-mounted to be carried by a stylus carrying shaft or body I0 and to contact in turn a record body 38.

The shaft I0 is supported at its inner end in a bearing II in the block F. The front end of shaft I0 is fixed into a block I2 which thus amounts to an extension of shaft I0. The block I2 is carried in a bearing I3 in the frame block F. The block I2 carries the stylus point or pin S and the latter is held therein by a set screw I4.

On block I2 there is mounted a friction collar I5 against which there is pressed a flanged ring l6 thereby producing sufficient friction to cause this ring I6 to vibrate with shaft I0 and block I2 but not to prevent the ring I6 from being adjusted by hand around the block I2.

The front end of block I2 is swaged over slightly at I! against a small collar I8, see Fig. 4, which collar holds the ring I6 against the friction collar I5.

On flanged ring I6 and on the small collar I8 there is held by frictional contact a cylindrical block I9 in which the reproducing stylus pin orpoint It is fixed by a set screw 20. By this con-Q struction the stylus pin R may be revolved from the operating service position to out of service position, as shown by the dotted lines in Fig. 5.

The recording stylus S is adjustedto cut the desired depth in a record groove or be held in. the correct depth of such a groove by a depth gage 2|. This gage has a contact finger 22 which rides on the record body 33 when desired to limit the depth of stylus S.

The finger 22 supports the weight of the stylus housing H of the arm A which is not sustained by the counter balance action of the spring Ii before described.

The gage 2| is supported by being fixed at its end by a screw 23 to the frame block F and is held from transverse movement by the screw 24 which latter screw is not necessarily clamped tightly to the block F. The finger 22 is adJusted to and from the depth relation? of it to the stylus S by a rod 25 screwed through the block F and contacting the gage 2| and by this means the finger 22 is adjusted to control the depth of the stylus point B in relation to the record 38.

In cutting a new record and also in reproducing a sound from a record the slight and very small variations in the surface of the record body are serious factors as modifying the character of the sound developed from the record. The finger 22 is as closely as commercially possible as to asso-. ciate its position to that of the stylus 8 whereby the finger 22 will cause the stylus to conform as nearly as possible to the depths produced by the exciting vibrations of the stylus of the sound which actuates the stylus or the sound which is produced through the medium of the stylus. This arrangement of the parts improves the quality of the service of this type of mechanism.

The amplitude of vibrations of the stylus point is dampened and shortened in both directions by means of a yoke 32 which is fixedto stylus shaft I and mounted on two screw studs 33 which are fixed in the frame block F. The yoke 32 is provided with two horizontal flanges 34 through which the studs 33 pass. On these flanges 34 there are mounted small discs of rubber 35 which take the place of or act like springs and these discs 35 are clamped on the studs 33 by metal washers 36 clamped by the screws 31 of the studs 33.

The amount of amplitude of the vibrations of the armature 26 is slight and the rubber spring washers .act in a rebounding function at either end of the amplitude of the armature 28 and this rebounding function assists in overcoming inertia of the weight of the moving parts and thereby aids in sensitivity of the service rendered by this mechanism.

The length of a rotatable stylus R is always longer than the stylus S and therefor when the stylus R contacts the record body thereby the whole stylus head is raised which thereby frees the stylus S from contacting the record. The stylus It may be frictionally adjusted for a considerable varying angle as relates to the direct vertical line to the record body, as shown by full lines in Fig. 5, and still function normally as a reproducing stylus, when in an angle less than the dotted line angle of Fig. 5.

To be able to make a slightly angular adjustment of the recording stylus R is particularly desirable when variable speed flat records are used. When I say variable speed for the record body this is produced in form to cause a constant speed of the stylus in the record body. The constant speed of the stylus on the sound track has such merits over the variable speed of the old style records that the constant speed sound use, particularly as relates to the higher quality of thesound results in phonograph machines.

Much amateur recording is engaged in in which frequently the cutting stylus becomes dull or the blank may be of a hard character. These things tend to slow down the cutting of the groove. When afterwards this sound track so, cut is reproduced, the variation in speed often changes the pitch of the sound to become a serious injury.

In the constant speed sound track machines which means a variable speed for the disc itself, my playback rotatable stylus R may be revolved at an angle ahead or back slightly as relates to what was the recording speed when that record was cut and this changing of time of travel by the revolving of my rotatable stylus R is used to correct the pitch adjustment of the sound produced.

0n the constant sound track speed record the swinging of my reproducing stylus R one quarter of an inch will change the pitch from tenor to bass and if so desired make up the difference between fifty and sixty cycles A. C. current. This permits adjustments as relates to the character of currents used in cutting as differentiated from reproducing any given sound track.

What I claim is:

1. In a mechanism of the class described, a stylus head, a stylus carrying shaft suitably mounted in said head, and an armature mounted 'on said stylus carrying shaft, an electrical exciting coil in association with said armature for exciting and being excited by the vibrations of the said armature on said stylus shaft, a stylus carrying block fixed on said stylus shaft, a fixed stylus point fixed into the said block, a cylindrical block mounted on the said stylus carrying block and rotatable thereon and held in place by frictional contact, a stylus point mounted in this cylindrical block and adapted to be rotated with the said cylindrical block, this rotatable stylus point longer in length than the said fixed stylus point, a fiat record carrying body located beneath the said stylus head and .adapted to be contacted alternately by the said fixed stylus and the said rotatable styluscan ried in its block, the latter stylus bein longer than the said fixed stylus as aforementioned to prevent the contact simultaneously of both stylus points with the record, the said rotatable stylus being rotated out of contact with the said record when the fixed stylus is to contact the record body.

2. A stylus carrying head mounted over a flat record carrying body, a stylus carrying shaft suitably mounted in said head in form to rotrack records are coming rapidly into general tatably vibrate, an armature mounted on said stylus carrying shaft, an electrical magnetic field mounted to be excited by the vibrations of said armature and also vibrate the said armature,

' two stylus points mounted on the said stylus shaft one of them being shorter than the other, the short one fixed to the said stylus shaft and the longer one rotatably mounted on said stylus shaft, and when this rotatable stylus is revolved to contact the record body, this results in lifting the shorter stylus up free of contact with the said by or excite the said armature on said shaft.

a flat record body mounted beneath the said a stylus head, a stylus point fixed in the said stylus carrying shaft and mounted to cut a record groove in the said record body. a rotatable stylus mounted in a rotatable block adapted to be revolved on the said stylus shaft, the said rotatable block fixed to the said rotatable shaft by frictional means whereby any desired position may be adjusted as relates to the contact 01' the said rotatable stylus to the said record body. this rotatable stylus point being longer than the said fixed stylus, the said fixed stylus being justment, this permitting the rotatable stylus to a contact exactly the sound track cut by the said fixed stylus when a slight movement or the record body has intervened between the alternate contacts of said stylus points.

EDWARD ROBERT HARRIS. 

